Vehicle seat occupancy detection systems are nowadays widely used in vehicles, in particular in passenger cars, for providing a seat occupancy signal for various appliances, for instance for the purpose of a seat belt reminder (SBR) system or an activation control for an auxiliary restraint system (ARS). Seat occupancy detection systems include seat occupancy sensors that are known to exist in a number of variants, e.g. based on capacitive sensing, on deformation sensing or on sensing of pressure/force. In order to meet requirements regarding easy integration and required robustness, weight-sensitive seat occupancy sensors have typically been arranged on the B-surface of a vehicle seat, i.e. between a foam body of a seat cushion and a seat pan or cushion-supporting springs of the vehicle seat.
Further, vehicle seat occupancy detection systems are known to be employed as a means of assessing a potential activation of an installed vehicle passenger restraint system, such as an airbag.
It is further known to employ detection systems for detecting a presence or absence of a driver's hands on the steering wheel of a vehicle. Such detection systems provide input, for instance, to automatic driver assistance systems (ADAS).
By way of example, patent application US 2002/0038947 A1 describes an occupant detecting apparatus for detecting an occupant seated on a passenger seat of a vehicle with an airbag for the occupant. A load sensor is provided in a bottom part of the seat. A plurality of first electric field sensors are provided in the bottom part of the seat, and a plurality of second electric field sensors are provided in a rear part of the seat. An airbag inflation permission control unit permits inflation of the airbag in accordance with output signals of the load sensor and the first and second electric field sensors.
Patent application US 20100228417 A1 describes a system and method for determining whether a vehicle driver is holding a steering wheel of the vehicle while the vehicle is in an autonomous driving mode. The vehicle will include an electric power steering (EPS) system and may include an active front steering (AFS) system, both of which include a motor that can apply a high frequency and low amplitude perturbation signal to the steering wheel of the vehicle that is not felt by the vehicle driver and does not cause the vehicle to turn, but is able to be detected by a steering angle sensor. The method subtracts a steering angle command signal from the steering angle signal and removes road disturbances, and then determines whether the induced perturbation signal is present in the steering angle sensor signal. If the perturbation signal is present, then the system knows that the vehicle driver is not holding the steering wheel.